this takedown of rudy giuliani was his most memorable. this was good work by biden. let's listen. >> the irony is rudy giuliani, probably the most underqualified man since george bush to seek the presidency, is here talking about the people here. rudy giuliani, there's only one things he mentioned in a sentence, a noun, a verb, and 9/11. >> i remember that line, very, very well. i had a ryan staffer tell me that they were going back and looking at some of the research, that not only did biden do very well in his debates, but david plouffe, the obama strategist, wrote in his book part of the reason obama picked biden was because he was impressed with his debate performance. he's a 40-year veteran, and he's going to be a capable debater. when joe biden was debating in '87 and '88 when he ran for president the first time, paul ryan was in high school. so there's going to be, i think, a fascinating age gap there on that stage. joe biden is not somebody that's going to come out there and sort of stumble around. it's possible he could commit a gaffe, but the ryan folks tha